Buff MA - help to code(translate) it

ontherun · #1 (**permalink**) 09-10-2007, 08:59 PM

Hi,

as I'm not well-versed in MT4 coding I need help with a simple formula called Buff MA; I've the corresponding formula in Metastock language as the following one:

BUFF:=Sum(V*C, 32) / (Cum(V) - Ref( Cum(V), -32));
BUFF

If someone could compile it for MT4 I'd be glad.

Buff MA helps in determining the most probable side to trade... when price is above Buff and aligned with it* only long positions are allowed... viceversa for short ones.

*(that's if Buff and price both are upward it's OK to be long... viceversa for shorting)

Thanks a lot

ontherun

ps: I've been looking for the Sum() and Cum() corresponding functions in the MetaEditor but I've not found anything related to those functions...

ralph.ronnquist · #2 (**permalink**) 09-10-2007, 10:06 PM

Someone familiar with Metastock may correct me, but by the looks of it, you have a "BUFF" function that looks at the 32 most recent bars, adds up the volume times the close price for them, and divides that by the total volume for those bars. It could look like the following in MT4:

PHP Code:


			
double buff()

{

    double sum = 0;

    double v = 0;

    for ( int i = 0; i < 32; i++ ) {

        sum += Volume[ i ] * Close[ i ];

        v += Volume[ i ];

    }

    return( sum / v );

}

ontherun · #3 (**permalink**) 09-11-2007, 09:32 AM

Ralph,

thanks for taking time to answer me.

Your understanding of the formula I've posted is right and actually it could be written simpler, that's: BUFF:= Sum(V*C, 32) / Sum(V,32);

Anyway I've created a new indicator with your code but even if it compiled without errors it didn't plot anything.

below is the whole script I've written for the Buff MA:

PHP Code:


			
//+------------------------------------------------------------------+

//|                                                      Buff MA.mq4 |

//|                      Copyright © 2007, MetaQuotes Software Corp. |

//|                                        http://www.metaquotes.net |

//+------------------------------------------------------------------+

#property copyright "Copyright © 2007, MetaQuotes Software Corp."

#property link      "http://www.metaquotes.net"



#property indicator_chart_window

#property indicator_buffers 1



#property indicator_color1 Blue



double BUFF[];

//+------------------------------------------------------------------+

//| Custom indicator initialization function                         |

//+------------------------------------------------------------------+

int init()

  {

  string short_name;

  

  IndicatorBuffers(1);

  

//---- indicator lines

  SetIndexStyle(0,DRAW_LINE,STYLE_SOLID,2,Blue);

  SetIndexBuffer(0,BUFF);

  SetIndexLabel(0,"Buff MA");

  

//---- name for DataWindow and indicator subwindow label

   short_name="Buff MA";

   IndicatorShortName(short_name);

   

//----

   SetIndexDrawBegin(0,100);     

  

//----

   return(0);

  }

//+------------------------------------------------------------------+

//| Custom indicator deinitialization function                       |

//+------------------------------------------------------------------+

int deinit()

  {

//----

   

//----

   return(0);

  }

//+------------------------------------------------------------------+

//| Buff MA                                                          |

//+------------------------------------------------------------------+

int start()



  { 

    double sum=0; 

    double v=0; 

    for (int i=0; i<32; i++) { 

        sum+=Volume[i]*Close[i]; 

        v+=Volume[i];      

    } 

    return(sum/v); 

}  



//+------------------------------------------------------------------+

ralph.ronnquist · #4 (**permalink**) 09-11-2007, 10:35 AM

no, right; it will need to compute the value relative to prior bars, and assign BUFF with the values.... like

PHP Code:


			
int start()
{
    for ( int bar = Bars - IndicatorCounted(); bar >= 0; bar-- ) {
        indicate( bar );
    }
}

void indicate(int bar)
{
    double sum=0; 
    double v=0; 
    for ( int i=0; i<32; i++ ) {
        sum += Volume[ bar + i ] * Close[ bar + i ]; 
        v += Volume[ bar + i ];
    }
    BUFF[ bar ] = sum/v;
}

Just replace your start() function with the above two functions, and it should do the trick.

ontherun · #5 (**permalink**) 09-12-2007, 08:12 PM

Ralph,

as I ve not yet got it working, can you attach the formula as .mq4 file

Thanks

ontherun

Michel · #6 (**permalink**) 09-12-2007, 09:04 PM

You can try :

PHP Code:


			
int start()

{

    for ( int bar = Bars-32-IndicatorCounted(); bar >= 0; bar-- ) {

        indicate( bar );

    }

}

ontherun · #7 (**permalink**) 09-12-2007, 10:24 PM

Michel,

thanks for answering.

The Buff formula with your modification plots correct as for the calculated values (I compare them to those plotted by the Buff in Metastock) but it doesn't update... that's it stops plotting just at the bar developing the moment I attach it to the chart.

ontherun

Michel · #8 (**permalink**) 09-13-2007, 12:59 AM

You are right, so please try this code which should be the right way to code this kind of indic (I am not able to check it myself now):

PHP Code:


			
int start()

  {

   int i,counted_bars=IndicatorCounted();

   if(Bars<=32) return(0);

   if(counted_bars<1) for(i=1;i<=32;i++) BUFF[Bars-i]=EMPTY_VALUE;

   i=Bars-33;

   if(counted_bars>=32) i=Bars-counted_bars-1;

   while(i>=0)

     {

      indicate(i);

      i--;

     }

   return(0);

  }

ontherun · #9 (**permalink**) 09-14-2007, 05:23 PM

Great work!
Thanks, Michel.

Actually I didn't think coding this was so demanding comparing to Metastock language.

Thanks again and thanks to Ralph too.

Have a great weekend.

ontherun